Device for eliminating the trailing end that is formed in the film coming off wrapping machines for wrapping palletized loads when the reel of film is replaced

Abstract

A device for eliminating the trailing end of the film that is formed on wrapping machines for wrapping palletized loads when the reel of film is replaced, is of the type in which the wrapping machine is equipped with: a first, reel-holder, assembly, constituted by pre-stretching rollers driven by motor means, return idlers and a compensator arm; and a second, welding, assembly constituted by a gripper, welding means, and cutting means; the film sliding between the reel, said first assembly and said second assembly, and the load set on the pallet. Positioned between the reel and the first assembly is a mobile unit provided with a re-winding roller designed to press on the reel in operating conditions.

1. A device for eliminating the trailing end of film that is formed on wrapping machines for wrapping palletized loads when a reel of film is replaced, said device comprising:
 a first reel holder assembly having pre-stretching rollers driven by a reversible motor, return idlers and a compensator arm; 
 a second welding assembly having a gripper, a welder and a cutter, wherein the second assembly is movable between a first position for engaging the film and a second retracted position; 
 the film sliding between the reel, said first assembly, said second assembly, and the load set on the pallet; 
 a mobile unit positioned between the reel and the first assembly, the mobile unit having a re-winding roller at an extended end of the mobile unit and a guide configured to position the re-winding roller in engagement with the reel in operating conditions for driving rewinding of the reel; and 
 an actuator governed by a sensor for detecting running-out of the reel, wherein the film is wound around the sensor; 
 wherein the cutter is configured to cut the trailing end of the film on the palletized load that has been wrapped, and the welder is configured to weld the trailing end of the film with completion of the wrapping cycle and release of the cut-away end of the wrapping film by opening of said gripper; 
 wherein at the engaged position, the mobile unit extends and moves the re-winding roller into engagement with the reel; 
 wherein the reversible motor determines the direction of film travel along the path between the reel and the second assembly; and 
 wherein the re-winding roller is rotatable in the direction that determines re-winding of the reel engaging the roller when the mobile unit is extended and the re-winding roller engages the reel. 
 
   
   
     2. The device according to  claim 1 , wherein the mobile unit comprises a pneumatic guide having an oscillating end, wherein the rewinding roller is fixed to the oscillating end. 
   
   
     3. The device according to  claim 2 , wherein when the re-winding roller is idle and pushed against one of the motor-driven pre-stretching rollers, the motor drives the engaged pre-stretching roller to draw the film, so that the pre-stretching roller draws in rotation the re-winding roller and the reel. 
   
   
     4. The device according to  claim 2 , wherein the re-winding roller is motor-driven and only engages the reel in operating conditions.